A fully developed body paragraph follows a claim-evidence-analysis (CEA) pattern: a topic sentence states the paragraph's claim, specific evidence supports it, and analysis explains how and why that evidence proves the claim. Development depth — the ratio of analysis to evidence — is what separates competent writing from superficial writing; underdeveloped paragraphs present evidence and move on, while strong paragraphs interrogate what the evidence means and how it connects to the thesis. Paragraph unity requires that every sentence advance the topic sentence's claim, with no detours into adjacent points that deserve their own paragraph.
Color-code a draft paragraph: highlight claims in one color, evidence in another, and analysis in a third. If analysis is absent or thin, the paragraph needs development. Practice writing two sentences of analysis for every piece of evidence before learning to calibrate the ratio by audience and genre.
You already know two of the key ingredients for a strong body paragraph: how to write a focused topic sentence that states what the paragraph proves, and how to select evidence that supports a claim. The challenge is what comes between — and the gap most writers leave there is analysis. Think of a paragraph as a small, self-contained persuasive argument: the topic sentence is the claim, the evidence is the data, and the analysis is the reasoning that explains why the data supports the claim. Without the reasoning, a reader receives your evidence but is left to supply the interpretation themselves — and they won't supply yours.
The CEA pattern — Claim, Evidence, Analysis — is a structural model for ensuring nothing gets skipped. A topic sentence opens with the claim. Evidence (a quote, a statistic, a scene, an example) follows. Then comes analysis: not a summary of what the evidence says, but an explanation of what it *means* for the argument. Analysis answers implicit reader questions: "So what?" "How does this prove the claim?" "What does this example reveal that a different example wouldn't?" A single piece of evidence may require two or more analytical sentences to fully cash out its significance, depending on the complexity of what you're asking it to prove.
Development depth — the ratio of analysis to evidence — is what distinguishes a developed paragraph from an underdeveloped one. A paragraph that presents a quote and immediately pivots to the next piece of evidence treats evidence as self-explanatory, which it rarely is. Developed analysis names the mechanism: "This reveals that..." or "The significance of this detail is..." or "What makes this example compelling is..." This kind of analytical pivot forces you to be explicit about the reasoning that a reader might not supply on their own. A useful starting discipline: write at least two sentences of analysis for every piece of evidence before calibrating the ratio by audience and purpose.
Paragraph unity is the complementary discipline. Every sentence in the paragraph should advance the same topic sentence claim. A paragraph that starts arguing X and drifts toward an adjacent point Y is two paragraphs collapsed into one — each deserves its own space to develop fully. The test is simple: cover the topic sentence and read each subsequent sentence. Does each one visibly serve the stated claim, or has the paragraph taken a detour? If detour, break at that point and start a new paragraph with a new topic sentence that captures what the second half is actually arguing. Underdevelopment and lack of unity are the two most common structural flaws in body paragraphs, and they are solved by the same discipline: identify what each paragraph claims, then build every sentence in service of that claim.